Experimental and theoretical investigations of the [Ln(beta-dik)(NO3)(2)(phen)(2)]center dot H2O luminescent complexes
authors Santos, PRS; Pereira, DKS; Costa, IF; Silva, IF; Brito, HF; Faustino, WM; Neto, ANC; Moura, RT; Araujo, MH; Diniz, R; Malta, OL; Teotonio, EES
nationality International
journal JOURNAL OF LUMINESCENCE
keywords INTRAMOLECULAR ENERGY-TRANSFER; CHARGE-TRANSFER STATE; CRYSTAL-STRUCTURE; INTENSITY PARAMETERS; LANTHANIDE COMPLEXES; ELECTRONIC-STRUCTURE; DESIGN; TRANSITIONS; ABSORPTION; SPECTRA
abstract In this work, the coordination compounds presenting the formulas [Eu(acac)(NO3)(2) (phen)(2)]center dot H2O (Eu1) and [Eu(bzac)(NO3)(2)(phen)(2)]center dot H2O (Eu2), acac: acetylacetonate, bzac: benzoylacetonate and, phen: 1,10-phenantroline, were successfully synthesized and some spectroscopic properties were investigated by theoretical and experimental methods. These compounds were characterized via elemental analysis, FTIR spectroscopy and thermogravimetric analysis (TGA). The X-ray diffraction data revealed that the compound Eu1 crystallizes in the monoclinic space group P2/n. Spectroscopic data showed that ligand-to-metal charge transfer states (LMCT) in the [Eu(beta-dik)(NO3)(2)(phen)(2)]center dot H2O complexes (beta-dik: acac or bzac) are redshift as compared with [Eu(beta-dik)3(phen)] complexes. These data showed that LMCT states play the most important role on the luminescence quenching in the complexes Eu1 and Eu2, which only exhibit high luminescence intensities at low temperatures. Furthermore, the role of changes in the chemical environment on the intensity parameters Omega(lambda) (lambda = 2 and 4) have been investigated from the theoretical point of view for the complexes Eu1 to Eu2, and from these to tris beta-dik complexes. Interestingly, the theoretical intensity parameters ratio Omega(2)/Omega(4) calculated are in a good agreement with those experimental ones.
publisher ELSEVIER
issn 0022-2313
isbn 1872-7883
year published 2020
volume 226
digital object identifier (doi) 10.1016/j.jlumin.2020.117455
web of science category Optics
subject category Optics
unique article identifier WOS:000559071300014
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journal impact factor 3.28
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